In light of recent events, Paris Hilton, the world's most famous DUI offender, is the last person we expected to see at a party promoting sobriety.

Then again, as we learned in court last week, Hilton may not have had time to read the invite.

Hilton arrived Monday night at attorney Robert Shapiro's "Sober Day USA" event on the Paramount Studios lot in Los Angeles with sister Nicky and embattled publicist Elliot Mintz. The flack had resigned Sunday but at Monday night's event he told Us "the rumors of our professional separation were overexaggerated" and he was, at least for now, back on as Hilton's rep.

Bypassing the red carpet, Hilton kept a low-profile in a sleeveless silk dress and gold shoes. Later, she posed for pictures with Mintz and Robert Shapiro, who, in 2006, declared the first Monday in May "Sober Day" in memory of his drug-using late son, Brent.

Though Paris held it together, a witness tells Us her eyes were tearing.

Perhaps she remembered she has only 29 days left on the outside?

Regardless, Paris wasn't upset for long. She left Sober Day and headed to the Roxy, where she stood on top of her table and danced to the band Phantom Planet. Paris and Mintz were singing along to the group's hit "California." A source tells Us, "Paris looked happy to be out." She slipped out the back door as soon as the show ended at 12:50 AM.